1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2016 Red Hat
4 * Author: Rob Clark <robdclark@gmail.com>
5 */
6
7#include <linux/vmalloc.h>
8#include <linux/sched/mm.h>
9
10#include "msm_drv.h"
11#include "msm_gem.h"
12#include "msm_gpu.h"
13#include "msm_gpu_trace.h"
14
15/* Default disabled for now until it has some more testing on the different
16 * iommu combinations that can be paired with the driver:
17 */
18static bool enable_eviction = true;
19MODULE_PARM_DESC(enable_eviction, "Enable swappable GEM buffers");
20module_param(enable_eviction, bool, 0600);
21
22static bool can_swap(void)
23{
24 return enable_eviction && get_nr_swap_pages() > 0;
25}
26
27static bool can_block(struct shrink_control *sc)
28{
29 if (!(sc->gfp_mask & __GFP_DIRECT_RECLAIM))
30 return false;
31 return current_is_kswapd() || (sc->gfp_mask & __GFP_RECLAIM);
32}
33
34static unsigned long
35msm_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
36{
37 struct msm_drm_private *priv = shrinker->private_data;
38 unsigned count = priv->lru.dontneed.count;
39
40 if (can_swap())
41 count += priv->lru.willneed.count;
42
43 return count;
44}
45
46static bool
47purge(struct drm_gem_object *obj)
48{
49 if (!is_purgeable(to_msm_bo(obj)))
50 return false;
51
52 if (msm_gem_active(obj))
53 return false;
54
55 msm_gem_purge(obj);
56
57 return true;
58}
59
60static bool
61evict(struct drm_gem_object *obj)
62{
63 if (is_unevictable(to_msm_bo(obj)))
64 return false;
65
66 if (msm_gem_active(obj))
67 return false;
68
69 msm_gem_evict(obj);
70
71 return true;
72}
73
74static bool
75wait_for_idle(struct drm_gem_object *obj)
76{
77 enum dma_resv_usage usage = dma_resv_usage_rw(write: true);
78 return dma_resv_wait_timeout(obj: obj->resv, usage, intr: false, timeout: 10) > 0;
79}
80
81static bool
82active_purge(struct drm_gem_object *obj)
83{
84 if (!wait_for_idle(obj))
85 return false;
86
87 return purge(obj);
88}
89
90static bool
91active_evict(struct drm_gem_object *obj)
92{
93 if (!wait_for_idle(obj))
94 return false;
95
96 return evict(obj);
97}
98
99static unsigned long
100msm_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
101{
102 struct msm_drm_private *priv = shrinker->private_data;
103 struct {
104 struct drm_gem_lru *lru;
105 bool (*shrink)(struct drm_gem_object *obj);
106 bool cond;
107 unsigned long freed;
108 unsigned long remaining;
109 } stages[] = {
110 /* Stages of progressively more aggressive/expensive reclaim: */
111 { &priv->lru.dontneed, purge, true },
112 { &priv->lru.willneed, evict, can_swap() },
113 { &priv->lru.dontneed, active_purge, can_block(sc) },
114 { &priv->lru.willneed, active_evict, can_swap() && can_block(sc) },
115 };
116 long nr = sc->nr_to_scan;
117 unsigned long freed = 0;
118 unsigned long remaining = 0;
119
120 for (unsigned i = 0; (nr > 0) && (i < ARRAY_SIZE(stages)); i++) {
121 if (!stages[i].cond)
122 continue;
123 stages[i].freed =
124 drm_gem_lru_scan(lru: stages[i].lru, nr_to_scan: nr,
125 remaining: &stages[i].remaining,
126 shrink: stages[i].shrink);
127 nr -= stages[i].freed;
128 freed += stages[i].freed;
129 remaining += stages[i].remaining;
130 }
131
132 if (freed) {
133 trace_msm_gem_shrink(nr_to_scan: sc->nr_to_scan, purged: stages[0].freed,
134 evicted: stages[1].freed, active_purged: stages[2].freed,
135 active_evicted: stages[3].freed);
136 }
137
138 return (freed > 0 && remaining > 0) ? freed : SHRINK_STOP;
139}
140
141#ifdef CONFIG_DEBUG_FS
142unsigned long
143msm_gem_shrinker_shrink(struct drm_device *dev, unsigned long nr_to_scan)
144{
145 struct msm_drm_private *priv = dev->dev_private;
146 struct shrink_control sc = {
147 .nr_to_scan = nr_to_scan,
148 };
149 unsigned long ret = SHRINK_STOP;
150
151 fs_reclaim_acquire(GFP_KERNEL);
152 if (priv->shrinker)
153 ret = msm_gem_shrinker_scan(shrinker: priv->shrinker, sc: &sc);
154 fs_reclaim_release(GFP_KERNEL);
155
156 return ret;
157}
158#endif
159
160/* since we don't know any better, lets bail after a few
161 * and if necessary the shrinker will be invoked again.
162 * Seems better than unmapping *everything*
163 */
164static const int vmap_shrink_limit = 15;
165
166static bool
167vmap_shrink(struct drm_gem_object *obj)
168{
169 if (!is_vunmapable(to_msm_bo(obj)))
170 return false;
171
172 msm_gem_vunmap(obj);
173
174 return true;
175}
176
177static int
178msm_gem_shrinker_vmap(struct notifier_block *nb, unsigned long event, void *ptr)
179{
180 struct msm_drm_private *priv =
181 container_of(nb, struct msm_drm_private, vmap_notifier);
182 struct drm_gem_lru *lrus[] = {
183 &priv->lru.dontneed,
184 &priv->lru.willneed,
185 &priv->lru.pinned,
186 NULL,
187 };
188 unsigned idx, unmapped = 0;
189 unsigned long remaining = 0;
190
191 for (idx = 0; lrus[idx] && unmapped < vmap_shrink_limit; idx++) {
192 unmapped += drm_gem_lru_scan(lru: lrus[idx],
193 nr_to_scan: vmap_shrink_limit - unmapped,
194 remaining: &remaining,
195 shrink: vmap_shrink);
196 }
197
198 *(unsigned long *)ptr += unmapped;
199
200 if (unmapped > 0)
201 trace_msm_gem_purge_vmaps(unmapped);
202
203 return NOTIFY_DONE;
204}
205
206/**
207 * msm_gem_shrinker_init - Initialize msm shrinker
208 * @dev: drm device
209 *
210 * This function registers and sets up the msm shrinker.
211 */
212int msm_gem_shrinker_init(struct drm_device *dev)
213{
214 struct msm_drm_private *priv = dev->dev_private;
215
216 priv->shrinker = shrinker_alloc(flags: 0, fmt: "drm-msm_gem");
217 if (!priv->shrinker)
218 return -ENOMEM;
219
220 priv->shrinker->count_objects = msm_gem_shrinker_count;
221 priv->shrinker->scan_objects = msm_gem_shrinker_scan;
222 priv->shrinker->private_data = priv;
223
224 shrinker_register(shrinker: priv->shrinker);
225
226 priv->vmap_notifier.notifier_call = msm_gem_shrinker_vmap;
227 WARN_ON(register_vmap_purge_notifier(&priv->vmap_notifier));
228
229 return 0;
230}
231
232/**
233 * msm_gem_shrinker_cleanup - Clean up msm shrinker
234 * @dev: drm device
235 *
236 * This function unregisters the msm shrinker.
237 */
238void msm_gem_shrinker_cleanup(struct drm_device *dev)
239{
240 struct msm_drm_private *priv = dev->dev_private;
241
242 if (priv->shrinker) {
243 WARN_ON(unregister_vmap_purge_notifier(&priv->vmap_notifier));
244 shrinker_free(shrinker: priv->shrinker);
245 }
246}
247

source code of linux/drivers/gpu/drm/msm/msm_gem_shrinker.c